JP5813607B2 - Pattern forming method and method for producing lithography original - Google Patents

Description

  Embodiments described herein relate generally to a pattern forming method and a lithography original plate manufacturing method.

  As a lithography technique in the manufacturing process of a semiconductor element, a double patterning technique using ArF immersion exposure, EUV lithography, nanoimprint, and the like are known. The conventional lithography technique has various problems such as an increase in cost, a decrease in alignment accuracy, and a decrease in throughput as the pattern is miniaturized.

  Under such circumstances, application of the self-assembly (DSA) phenomenon to the lithography technique is expected. Since the self-assembled phase is generated by the spontaneous behavior of energy stability, a pattern with high dimensional accuracy can be formed. In particular, a technique using microphase separation of a polymer block copolymer can form periodic structures of various shapes of several to several hundreds of nm with a simple coating and annealing process. Holes, pillars, and line patterns with various dimensions can be formed by changing the microdomain structure into spherical, columnar, layered, etc. depending on the block composition ratio of the polymer block copolymer, and changing the size depending on the molecular weight. .

JP 2011-77475 A

  An object of the present invention is to provide a pattern forming method and a lithography original plate manufacturing method capable of reducing an error in the relative positional relationship between a self-organized pattern and another pattern.

  According to this embodiment, the pattern forming method forms a self-assembled pattern by forming a self-assembled material on a substrate on which a reference mark is formed, and microphase-separating the self-assembled material. And a step of measuring a position error from a predetermined position of the formation position of the self-assembled pattern based on the reference mark, and a step of forming an alignment pattern and a peripheral circuit pattern on the substrate. ing. The formation position of at least one of the alignment pattern and the peripheral circuit pattern is corrected using the position error.

It is sectional drawing and the top view explaining the pattern formation method by this embodiment. It is sectional drawing and the top view which show the process following FIG. FIG. 3 is a cross-sectional view and a top view showing a process following FIG. 2. FIG. 4 is a cross-sectional view and a top view showing a process following FIG. 3. It is sectional drawing and the top view which show the process following FIG. FIG. 6 is a cross-sectional view and a top view illustrating a process following FIG. 5. FIG. 7 is a cross-sectional view and a top view showing a step following FIG. 6. FIG. 8 is a cross-sectional view and a top view showing a step following FIG. 7. FIG. 9 is a cross-sectional view and a top view showing a step following FIG. 8. FIG. 10 is a cross-sectional view and a top view illustrating a process following FIG. 9. It is sectional drawing and the top view which show the process following FIG. FIG. 12 is a cross-sectional view and a top view illustrating a process following FIG. 11. It is sectional drawing and the top view which show the process following FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 12 are diagrams for explaining the pattern forming method according to the present embodiment.

  First, as shown in FIGS. 1A and 1B, a photomask substrate in which a light shielding film 102 is provided on a glass substrate 101 is prepared. FIG. 1B is a top view, and FIG. 1A is a cross-sectional view taken along line II in FIG. 1B. The light shielding film 102 is a film containing, for example, chromium or tantalum. This photomask substrate is formed with a reference mark FM for pattern position measurement. The reference mark FM may be formed on the light shielding film 102 or may be formed on the glass substrate 101.

  Next, as shown in FIGS. 2A and 2B, a base film 103 is formed on the photomask substrate. 2B is a top view, and FIG. 2A is a cross-sectional view taken along line II-II in FIG. 2B. The base film 103 serves as a base for a block copolymer formed in a later step. In the base film 103, the surface state of the region irradiated with light of a predetermined wavelength changes. For example, the base film 103 has hydrophobicity before light irradiation, and the region irradiated with light changes to hydrophilic.

  As the base film 103, for example, a laminated film of a self-assembled monomolecular film layer and a polymer layer can be used. For the self-assembled monolayer, a silane coupling agent containing a benzophenone skeleton can be used. Moreover, a (meth) acrylic resin derivative can be used for a polymer. In the light irradiation region of the laminated structure of the self-assembled monomolecular film layer and the polymer, cross-linking with the polymer in contact with the benzophenone structure occurs, so that the surface is derived from the polymer. By using a hydrophilic resin such as a (meth) acrylic resin as the polymer, the light irradiation part can be in a hydrophilic state.

  Next, as shown in FIGS. 3A and 3B, a resist is applied on the base film 103, and exposure and development are performed to form a frame pattern 104 surrounding the region R1. 3B is a top view, and FIG. 3A is a cross-sectional view taken along line II-II in FIG. 3B. The region R1 is a region where a block copolymer is formed in a later step. The region R1 is, for example, a region corresponding to the memory cell unit, but is not limited to the memory cell unit as long as it is a pattern region formed at an equal interval pitch.

  Here, the resist used as the material of the frame pattern 104 may be a material having a neutral property with respect to two polymers (first polymer and second polymer) included in a block copolymer formed in a later step. preferable. That is, it is preferable to have a surface energy that is approximately between the surface energy of the first polymer and the surface energy of the second polymer.

  Next, as shown in FIGS. 4A and 4B, a predetermined region of the base film 103 is exposed using a light shielding mask (not shown). 4B is a top view, and FIG. 4A is a cross-sectional view taken along line II-II in FIG. 4B. The light to be irradiated is light having a wavelength that the base film 103 is exposed to, for example, light having a UV to DUV wavelength (365 nm, 248 nm, 193 nm, etc.). Of the base film 103, the exposed portion 103a changes to hydrophilic, and the unexposed portion remains hydrophobic. For example, as shown in FIGS. 4A and 4B, in a region R1 surrounded by the frame pattern 104, exposure is performed in a line shape with a predetermined pitch. As a result, the base film 103 in the region R1 surrounded by the frame pattern 104 becomes a chemical guide layer that controls the formation position of the microphase separation pattern when the block copolymer formed in the subsequent process undergoes microphase separation. . Next, as shown in FIGS. 5A and 5B, a block copolymer layer 105 is formed on the base film 103 in the frame pattern 104. 5B is a top view, and FIG. 5A is a cross-sectional view taken along the line II-II in FIG. 5B. As the block copolymer, for example, a diblock copolymer in which a first polymer block chain and a second polymer block chain are bonded is used. As the diblock copolymer, for example, a block copolymer of polystyrene (PS) and polymethyl methacrylate (PMMA) can be used. The presence of the frame pattern 104 can prevent the block copolymer from leaking outside the frame pattern 104.

  Next, as shown in FIGS. 6A and 6B, the substrate is heated using a hot plate (not shown), the block copolymer layer 105 is microphase-separated, and a thin plate shape including the first polymer block chain is formed. The lamellar self-assembled pattern 106 in which the first polymer portions 106a and the thin plate-like second polymer portions 106b including the second polymer block chain are alternately arranged is formed. 6B is a top view, and FIG. 6A is a cross-sectional view taken along the line II-II in FIG. 6B.

  The lamellar self-assembled pattern 106 is formed by forming a base film 103 having a portion 103a whose surface state is changed by exposure and a portion whose surface state is not changed as a chemical guide layer. Further, as described above, since the frame pattern 104 has a neutral property with respect to the first polymer and the second polymer, the influence on the arrangement of the self-assembled pattern 106 can be suppressed.

  Next, the formation position of the self-organized pattern 106 is measured based on the reference mark FM. For example, SEM is used for the measurement. Then, a position error between the measurement position and the target position is calculated. For example, the position of the center of gravity of each of the first polymer portion 106a and the second polymer portion 106b of the lamellar self-assembly pattern 106 is measured, and the position error from the target position is calculated. Further, the position error of the entire self-organized pattern 106 may be further calculated from the position error of each pattern (the first polymer portion 106a and the second polymer portion 106b).

  Next, as shown in FIGS. 7A and 7B, either one of the first polymer portion 106a and the second polymer portion 106b in the self-assembled pattern 106 is selectively removed by development processing. Here, the first polymer portion 106a is removed. 7B is a top view, and FIG. 7A is a cross-sectional view taken along the line II-II in FIG. 7B.

  Next, as shown in FIGS. 8A and 8B, a resist 107 is applied on the base film 103 outside the frame pattern 104. 8B is a top view, and FIG. 8A is a cross-sectional view taken along the line II-II in FIG. 8B.

  Next, as shown in FIGS. 9A and 9B, exposure / development is performed to form an alignment pattern 110 and a peripheral circuit pattern 111 on the resist 107. For example, an electron beam is used for exposure. FIG. 9B is a top view, and FIG. 9A is a cross-sectional view taken along line III-III in FIG. 9B. The formation positions of the alignment pattern 110 and the peripheral circuit pattern 111 are corrected so that the relative positional relationship with the self-organized pattern 106 approaches the design value.

  For example, with respect to the alignment pattern 110, the formation position is corrected by adding a position error of the calculated self-organized pattern 106 as a whole to the initial formation position (exposure position in the design information).

  Further, for example, when the region R1 corresponds to the memory cell portion and the peripheral circuit pattern 111 corresponds to the lead-out portion of the memory cell, the peripheral circuit pattern 111 has a plurality corresponding to the plurality of removed first polymer portions 106a. Pattern 111a. In this case, the formation position is corrected by adding the position error of the corresponding first polymer portion 106a to the initial formation position (exposure position in the design information) of each pattern 111a. That is, the formation position of the peripheral circuit pattern 111 is corrected for each pattern 111a.

  Next, as shown in FIGS. 10A and 10B, the frame pattern 104 is selectively removed. FIG. 10B is a top view, and FIG. 10A is a cross-sectional view taken along the line II-II in FIG. 10B.

  Next, as shown in FIGS. 11A and 11B, a resist 120 is applied to the region from which the frame pattern 104 has been removed. Then, a connection pattern 121 that connects the first polymer portion 106 a of the self-organized pattern 106 and the corresponding pattern 111 a of the peripheral circuit pattern 111 is formed on the resist 120 by exposure and development. FIG. 11B is a top view, and FIG. 11A is a cross-sectional view taken along line IV-IV in FIG.

  Next, as shown in FIGS. 12A and 12B, the base film 103 and the light shielding film 102 are etched using the resist 107, the resist 120, and the second polymer portion 106b as a mask. FIG. 12B is a top view, and FIG. 12A is a cross-sectional view taken along the line IV-IV in FIG.

  Next, as shown in FIGS. 13A and 13B, the resist 107, the resist 120, the second polymer portion 106b, and the base film 103 are removed. FIG. 13B is a top view, and FIG. 13A is a cross-sectional view taken along the line IV-IV in FIG. 13B. As a result, the first polymer portion 106a of the self-assembled pattern 106, the alignment pattern 110, the peripheral circuit pattern 111, and the connection pattern 121 are transferred to the light shielding film 102 on the glass substrate 101, and the photomask substrate (lithographic original plate) Is obtained.

  The alignment pattern 110 and the peripheral circuit pattern 111 are corrected in consideration of a shift in the formation position of the self-organized pattern 106. Therefore, errors in the positional relationship between the self-organized pattern 106, the alignment pattern 110, and the peripheral circuit pattern 111 can be reduced.

  Thus, according to the present embodiment, errors in the relative positional relationship between the self-organizing pattern and other patterns can be reduced even when the formation position of the self-organizing pattern is shifted.

  In the above embodiment, the formation position of the self-assembly pattern 106 is measured and the position error from the target position is calculated. However, after the first polymer part 106a of the self-assembly pattern 106 is removed, the formation of the second polymer part 106b is performed. A position error may be calculated by measuring the position. Alternatively, the position error from the target position may be calculated by measuring the position where the removed first polymer portion 106a is formed.

  Further, after the formation of the peripheral circuit pattern 111, the formation position of the connection pattern 121 (exposure position) may be corrected by measuring the formation position of the peripheral circuit pattern 111 and calculating the position error with respect to the target position.

  The exposure is not limited to the electron beam, and EUV light, UV light, ion beam, X-ray, visible light, infrared light, or the like may be used. Further, the frame pattern 104, the alignment pattern 110, the peripheral circuit pattern 111, and the connection pattern 121 may be formed by imprint processing.

  In the above embodiment, the glass substrate 101 is processed using the light shielding film 102 onto which the first polymer portion 106a of the self-organizing pattern 106, the alignment pattern 110, the peripheral circuit pattern 111, and the connection pattern 121 are transferred, as an imprint. A template may be produced.

  In the above embodiment, the formation positions of the alignment pattern 110 and the peripheral circuit pattern 111 are corrected. However, only one of the formation positions may be corrected. If the position error between the formation position of the self-organization pattern 106 and the target position is within a predetermined range, the formation position of the alignment pattern 110 and / or the peripheral circuit pattern 111 may not be corrected. .

  In the above embodiment, the connection pattern 121 may be formed using microphase separation of a self-organizing material. For example, a self-assembled pattern corresponding to the connection pattern 121 is formed using a self-assembled material including a polymer having a high affinity with the second polymer portion 106 b of the self-assembled pattern 106 and the surface of the resist 107. Further, the surface state of the second polymer portion 106b and the resist 107 of the self-assembled pattern 106 may be modified, and a self-assembled material including a polymer having a high affinity with the modified surface may be used. Alternatively, a chemical guide layer corresponding to the connection pattern 121 may be formed in the region from which the frame pattern 104 has been removed, and a self-organizing material may be applied on the chemical guide layer. Since the self-organizing material undergoes microphase separation in accordance with the second polymer portion 106b and the resist 107, even if the position of the first polymer portion 106a or the peripheral circuit pattern 111 is slightly shifted, the first polymer portion 106a and the peripheral circuit are arranged. A connection pattern 121 for connecting the pattern 111 can be formed.

  In the above embodiment, the chemical guide layer is formed in the frame pattern 104. However, when the frame pattern 104 is used as a physical guide, the block copolymer layer 105 is microphase-separated to obtain the self-assembled pattern 106. The chemical guide layer may be omitted. In that case, the frame pattern 104 includes a material having a high affinity with one of the two polymers included in the block copolymer layer 105.

  In the above-described embodiment, an example in which the lamellar self-assembled pattern 106 is formed has been described, but other shapes such as a cylinder may be used.

  In the above embodiment, a glass substrate is used as the substrate to be processed. The glass substrate is, for example, a quartz glass substrate or a sapphire glass substrate. Further, a substrate constituting an EUV lithography mask original, EB character aperture, optical imprint, thermal imprint original, or the like may be used as a substrate to be processed.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 101 Glass substrate 102 Light shielding film 103 Underlayer film 104 Frame pattern 105 Block copolymer layer 106 Self-organizing pattern 107 Resist 110 Alignment pattern 111 Peripheral circuit pattern 120 Resist 121 Connection pattern

Claims (7)

Forming a self-assembled material including a first segment and a second segment on a substrate on which a fiducial mark is formed;
Performing a heat treatment to microphase-separate the self-assembled material to form a self-assembled pattern having a first portion including the first segment and a second portion including the second segment;
Measuring a position error from a predetermined position of the formation position of the self-organization pattern, the first portion, or the second portion based on the reference mark;
Forming an alignment pattern and a peripheral circuit pattern on the substrate;
With
Pattern forming method of the formation position of the alignment pattern and the peripheral circuit pattern, and correcting by using the position error. The self-organizing pattern has a plurality of the first portions,
The peripheral circuit pattern has a plurality of circuit patterns corresponding to the first portion,
The pattern forming method according to claim 1 , wherein a position where each circuit pattern is formed is corrected using a position error of each of the first portions. Forming a frame pattern surrounding a predetermined area on the substrate;
The self-organizing material is formed in the frame pattern;
Selectively removing the first portion after microphase separation of the self-assembled material;
The frame pattern is selectively removed, and a connection pattern that connects the peripheral circuit pattern and the region from which the first portion is removed is formed in a region where the frame pattern is formed. The pattern forming method according to claim 1 . The pattern forming method according to claim 3 , wherein a resist is applied to a region where the frame pattern is formed, and the resist is processed by exposure and development to form the connection pattern. Applying a second self-organizing material including a third segment and a fourth segment to the region where the frame pattern was formed,
Heat treating to microphase-separate the second self-assembled material to form a second self-assembled pattern having a third portion including the third segment and a fourth portion including the fourth segment;
The pattern forming method according to claim 3 , wherein the connection pattern is formed by selectively removing the third portion. It said frame pattern to form a chemical guide layer in the pattern forming method according to any one of claims 1 to 5, characterized in that to form the self-organizing material in the chemical guide layer. The pattern forming method according to claim 6 , wherein the frame pattern has a neutral property with respect to the first segment and the second segment.

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